The KDE Software Compilation 4.3.4 release freezes the features for the upcoming 4.4, hence the code-name.
The last release in the 4.3 Software Compilation (SC) series provides a handful of bugfixes, such as in the Okular document viewer and the Marble desktop atlas software. Okular now actually stops the search when clicking the X button in the Find bar and Marble shows the correct altitude in navigation mode. The KGpg interface for GnuPG now recognizes passphrases with non-ASCII characters.
The first beta for the KDE SC 4.4 is scheduled for December 4, according to Sebastian Kügler. Further fixes for 4.3 are in the changelog, which includes links to the SVN entries. The project suggests 4.3.4 as a "recommended upgrade for everyone running 4.3.3." Source downloads and installation guidelines are available in the product announcement.